Dark-leaved willow

How to recognise it

Growth habit

Deciduous, upright to spreading shrub of 1–4 m, sometimes a small tree. Dioecious: male and female catkins grow on separate shrubs.

Twigs

Dark brown to blackish brown, densely and finely downy when young, later partly hairless. At the base of the leaf stalk there are often conspicuous, ear-shaped stipules.

Leaf

Elliptic to obovate, 2–7 cm, with finely toothed edges. Dark green and slightly glossy above, usually blue-grey with a bloom beneath, with a green tip. Turns black as it wilts and dries.

Flower

Catkins of 2–4 cm that appear with or just before the leaves, in April–May. Male catkins with yellow anthers, female ones greenish.

Fruit/Seed

Small capsules that split open in June, releasing tiny seeds with white fluff that blows away on the wind.

Confusion with

Tea-leaved willow (Salix phylicifolia) has hairless twigs and glossier leaves that do not turn black when dried. Grey willow (Salix cinerea) has grey, hairy leaves, and eared willow (Salix aurita) small, wrinkled leaves with wavy edges. Willows hybridise easily, so some shrubs are hard to name.

Flowering: April–May · Pruning: February–March

Why grow it?

• The catkins in April–May give pollen and nectar to honeybees, bumblebees, mining bees and hoverflies.
• Willows are food plants for a huge number of insects: the caterpillars of the puss moth and the eyed hawk-moth, among others, feed on the leaves.
• All those insects in turn feed tits, willow warblers and other songbirds.
• A sturdy, fast-growing shrub for a wet corner, a pond edge or a stream bank.
• An unusual northern willow with a surprising feature: its leaves turn black as they dry.

Dark-leaved willow: where does it grow best?

• In the wild: banks of rivers, streams and lakes, gravel bars, wet grassland, marshes and scrub, in northern Europe and in the mountains.
• In the garden: sun to light partial shade; in shade it grows sparse and flowers less.
• Moist to wet soil, preferably neutral to chalky; it tolerates temporary flooding and a cold, wet spot.
• Do not plant it close to sewers, drains or foundations: willow roots actively seek out water.

Goes well with

• Meadowsweet: Creamy, fragrant plumes in summer on the same wet soil.
• Purple loosestrife: Purple spikes in July–August, a nectar source for bees and butterflies at the water’s edge.
• Yellow iris: Yellow flowers in May–June at the water’s edge, at the foot of the willow.
• Hemp-agrimony: Late flowers in August–September, much loved by butterflies.
• Alder buckthorn: Another shrub of wet ground, which flowers for months for bumblebees and is a food plant of the brimstone butterfly.

Dark-leaved willow: when and how to plant it?

1. Buy it from a nursery that grows willows or wild European shrubs. Never take plants from the wild, not even on holiday in the mountains or in Scandinavia.
2. Plant from November to March, when the soil is not frozen: willows establish easily at that time.
3. Dig a planting hole slightly wider than the root ball; on poor soil, mix in some compost.
4. Allow 2–3 m of space per shrub; in a mixed hedge on wet ground, plant 1 m apart.
5. Water well straight away and regularly in dry spells during the first year: a young willow must not dry out.
6. If you already have a shrub, a sturdy winter cutting of 30 cm, pushed two thirds of its length into moist soil, usually grows into a new plant by itself.

Care

Water

Regularly in dry spells during the first year. After that no longer needed in a wet spot; on ordinary garden soil, water generously in dry summers.

Feeding

Not needed. On moist, fertile soil it grows fast enough on its own.

Coppicing

To keep it low and dense, cut it back to 30–50 cm above the ground every 3–5 years in February–March; it regrows vigorously.

Mulching

A layer of leaves or wood chips around a young plant keeps the soil moist.

Position

Keep it away from pipes and foundations: willow roots get into leaking pipes.

Tip: Not sure you have a true dark-leaved willow? Pick a leaf in autumn and let it dry for a few days: if it turns black, you have the right one.

Pruning and mowing

Pruning months: February–March.

When: Thin out or coppice in February–March, before the leaves come out and before birds start nesting.

How:

• Every few years, remove a few of the oldest branches at the base: this keeps the shrub young and dense.
• Cut out dead, broken and crossing branches.
• To keep it low, coppice it completely to 30–50 cm every 3–5 years; if you have several shrubs, do not cut them all in the same year.
• Prune only some of the branches each year, so you have catkins for the bees every spring.

Caution: Do not prune in the nesting season, from April to July. Whatever you cut back in winter will not flower that spring: the catkin buds are already on the branches.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Winter cuttings

Between November and March, push pencil-thick twigs of 20–30 cm two thirds of their length into moist soil. Willows root very easily: most cuttings take.

Summer cuttings

Green cuttings of 10–15 cm taken in June root quickly in a glass of water or in moist cutting compost.

Seed

Willow seed stays viable for only a short time. Sow it in June, as soon as it is shed, on moist compost. Seedlings may be hybrids with other willows.

Dark-leaved willow: how does it get through the winter?

Hardy to −35 °C.

• Drops its leaves in autumn; once fallen, they quickly turn dark to black.
• Extremely hardy, down to about −35 °C: a northern species that needs no protection.
• In winter the dark, downy twigs with the buds of next spring’s catkins are easy to see.
• Leave the fallen leaves in place: they shelter insects and feed the soil life.

Diseases and pests

• Sawfly galls: Red or green ‘beans’ on the leaves are galls made by small sawflies. Harmless and interesting: no need to do anything.
• Willow rust: Orange spots on the undersides of the leaves in late summer. Usually harmless; an open, airy spot helps.
• Willow leaf beetle: Small, shiny beetles and their larvae reduce the leaves to skeletons. Birds eat many of them and a willow usually recovers quickly.
• Roots in pipes: Willow roots seek water and get into leaking pipes. Plant it well away from sewers and drains.
• Drought: On dry soil it drops its leaves early in summer. Choose a moist spot or water it.

Through the year

• January: Rest: dark, downy twigs with fat buds.
• February: Thin out or coppice. Take and plant winter cuttings.
• March: Last pruning before the nesting season. Plant.
• April: Catkins and young leaves: bees, bumblebees and mining bees flock to them.
• May: Last catkins. Caterpillars on the leaves: tits and willow warblers find food there.
• June: Willow fluff: the seeds blow away. Take summer cuttings. Water young plants in dry spells.
• August: Sawfly galls on the leaves: harmless.
• October: The leaves fall and turn black. Plant.
• November: Plant and push in winter cuttings. Leave fallen leaves in place.
• December: Take winter cuttings.

Did you know?

• The old scientific name Salix nigricans means ‘blackening willow’: in a herbarium the pressed leaves turn almost black.
• Myrsinifolia means ‘with leaves like Myrsine’, a genus of evergreen shrubs from warmer regions.
• The word salicylic acid comes from Salix: in the nineteenth century a substance called salicin was extracted from willow bark.